The present invention relates generally to semiconductor fabrication and, more particularly, to a nozzle and a method for rinsing the backside of a semiconductor wafer.
As the semiconductor industry moves to larger, e.g., 300 mm, wafers and to smaller, e.g., 0.18 xcexcm and smaller, feature sizes, it is becoming increasingly more important to rinse effectively and to control wafer contamination on the bottom side, i.e., the backside, of wafers during wafer preparation operations. In one conventional brush station, the exit rinse manifolds, which are located at the exits from the first and second brush boxes of the brush station, include lower nozzles positioned to spray deionized (DI) water onto the backside of a wafer. To provide the DI water sprayed from these lower nozzles with a path to the center portion of the backside of a wafer, an aperture is provided in the wafer transport truck that carries the wafer through the exit rinse manifold. This aperture, however, does not permit an effective amount of the DI water sprayed from the lower nozzles to reach the center portion of the backside of a wafer. Thus, the lower nozzles in the exit rinse manifold do not thoroughly rinse the backside of a wafer.
In view of the foregoing, there is a need for a method and device for rinsing a backside of a wafer that ensures that the backside of a wafer is thoroughly rinsed.
Broadly speaking, the present invention fills this need by providing a nozzle that may be used to rinse the backside of a semiconductor wafer. The present invention also provides a method for rinsing the backside of a semiconductor wafer.
In accordance with one aspect of the present invention, a nozzle is provided. The nozzle includes a body having an entrance location and an exit location. The body has a curved exit surface defined at the exit location. An internal chamber is defined in the body below the curved exit surface and a channel extends between the entrance location and the internal chamber. A slit defines an opening in the curved exit surface. The slit extends from the curved exit surface into the internal chamber. The curved exit surface and the slit are configured to define a fanned spray when liquid flows out of the slit.
In one embodiment, the opening in the curved exit surface defines an elliptical path. In one embodiment, the slit is oriented at an angle of about 15 degrees to about 50 degrees relative to a horizontal plane. In a preferred embodiment, the slit is oriented at an angle of about 30 degrees to about 35 degrees relative to a horizontal plane. In one embodiment, the fanned spray is directed toward a center portion of a backside of a semiconductor wafer.
In one embodiment, the body is a wafer transport truck. In one embodiment, the fanned spray has a width greater than a width of the wafer transport truck. In one embodiment, the wafer transport truck is disposed in a brush station. In one embodiment, the wafer transport truck is disposed proximate to an exit from a first brush box. In another embodiment, the wafer transport truck is disposed proximate to an exit from a second brush box.
In accordance with another aspect of the present invention, a method for rinsing the backside of a semiconductor wafer is provided. In this method a wafer transport truck is first formed into a nozzle. A liquid is then sprayed from the nozzle onto a backside of a semiconductor wafer.
In one embodiment, the nozzle is configured to direct a fanned liquid spray toward a center portion of the backside of the semiconductor wafer. In one embodiment, the nozzle includes a curved surface in which a slit is defined. In one embodiment, the nozzle is disposed in a brush station. In one embodiment, the nozzle is disposed just before an exit from a first brush box. In another embodiment, the nozzle is disposed just before an exit from a second brush box.
The nozzle of the present invention enables the backside of a semiconductor wafer to be thoroughly rinsed. This is beneficial because it not only helps minimize particle contamination on the backside of the wafer, but also neutralizes the pH of the surface of the backside of the wafer.
It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.